1. Field of the Invention
This invention relates to a sulfur-containing unsaturated carboxylate comprising a sulfur-containing substituent and at least two xcex1,xcex2-unsaturated carboxylic acid residues via an oxygen atom attached to a secondary or tertiary carbon atom. This invention also relates to a polymerizable composition comprising the sulfur-containing unsaturated carboxylate compound and to an optical component produced by polymerizing the polymerizable composition.
A sulfur-containing unsaturated carboxylate compound according to this invention has a structural feature that it intramolecularly comprises a sulfur-containing substituent and at least two xcex1,xcex2-unsaturated carboxylic acid residues, which are each attached to a secondary or tertiary carbon atom via an oxygen atom.
The sulfur-containing unsaturated carboxylate compound is useful as a monomer for a polymerizable composition which is photocurable or thermosetting, and is suitably used in a variety of materials such as optical materials and dental materials. An optical component produced by curing the polymerizable composition has excellent optical, thermal and mechanical properties; can be produced in an improved yield; has a higher refractive index; and is useful in various applications such as a variety of plastic lenses (typically, an orthodontic eyeglass), optical information recording media, plastic substrates for a liquid crystal cell and optical-fiber coatings.
2. Description of the Prior Art
Inorganic glasses have a number of excellent physical properties such as excellent transparency and a reduced optical anisotropy, and thus has been used as a transparent optical material in various applications. The glasses, however, have problems such as fragility due to their heavy weight and a poor productivity, leading to recent intensive attempts for developing an optical resin as a substitute for an inorganic glass.
An essential property is transparency for an optical material. To date, various industrial resins with good transparency are known; for example, polymethyl methacrylate (PMMA), bisphenol-A-polycarbonate (BPA-PC), polystyrene (PS), methyl methacrylate-styrene copolymer (MS), styrene-acrylonitrile copolymer (SAN), poly(4-methylpentene-1) (TPX), polycycloolefin (COP), poly(diethyleneglycol bisallylcarbonate) (EGAC) and polythiourethane (PTU).
PMMA exhibits good transparency, weather resistance and moldability, but has drawbacks such as a lower refractive index (nd) of 1.49 and a higher absorbency.
BPA-PC exhibits good transparency, heat resistance and shock resistance and a higher refractive index, but a larger chromatic aberration, which limits its application.
PS and MS exhibit good moldability and transparency as well as have a lower absorbency and a higher refractive index, but exhibit lower shock resistance, weather resistance and heat resistance. They have been, therefore, rarely used as an optical resin in practice.
SAN is believed to have a relatively higher refractive index and well-balanced mechanical properties, but it is inadequately heat resistant (heat-distortion point: 80 to 90xc2x0 C.) to be used as an optical resin.
TPX and COP exhibit good transparency, lower absorbency and good heat resistance, but have drawbacks such as a lower refractive index (nd=1.47 to 1.53), lower shock resistance, lower gas barrier property and poor dye-affinity.
EGAC is a thermosetting resin from diethyleneglycol bisallylcarbonate monomer, which is most frequently used for a general-purpose eyeglass. It exhibits good transparency, good heat resistance and a minimal chromatic aberration, but has drawbacks such as a lower refractive index (nd=1.50) and lower shock resistance.
PTU is a thermosetting resin prepared by reaction of a diisocyanate with a polythiol, which is most frequently used for a superhigh refractive index eyeglass. It is an excellent material with good transparency, good shock resistance, a higher refractive index and a lower chromatic aberration, but has only one drawback of a longer duration for thermal-polymerization molding (1 to 3 days); i.e. , there is a problem in productivity.
To reduce duration for polymerization or curing for improving the above yield, various procedures have been suggested, including a process for manufacturing an optical lens by optical polymerization using bromine- or sulfur-containing acrylates; for example, JP-A 4-161410 and JP-A 3-217412. According to the process, polymerization can be conducted in a reduced period, but an obtained resin is not satisfactory as an optical component. For example, when it is used as an eyeglass, a resin with a higher refractive index is fragile and has a higher specific gravity. Thus, a material has been earnestly desired, which can solve these problems.
As described above, optical resins of the prior art have good properties, but they have their specific problems to be solved. Thus, it has been earnestly desired to develop an optical resin with good optical, mechanical and thermal properties as well as a good productivity and a higher refractive index.
Thus, an object of this invention for solving the drawbacks in a conventional optical resin is to provide an optical resin with good optical, mechanical and thermal properties as well as a good productivity and a higher refractive index.
We have intensely attempted to solve the problems to achieve this invention.
This invention provides the followings:
 less than 1 greater than  A sulfur-containing unsaturated carboxylate compound comprising a sulfur-containing substituent and at least two xcex1,xcex2-unsaturated carboxylic acid residues, which are each attached to a secondary or tertiary carbon atom via an oxygen atom.
 less than 2 greater than  A sulfur-containing unsaturated carboxylate compound represented by general formula (1). 
wherein R11 represents a bivalent organic group; each X11 independently represents oxygen, sulfur, xe2x80x94COOxe2x80x94 or xe2x80x94(CH2)lX12xe2x80x94 (X12 represents oxygen or sulfur and l is an integer of 1 to 3); each R12 independently represents hydrogen or alkyl; each R13 independently represents a sulfur-containing substituent; and each R14 independently represents an xcex1,xcex2-unsaturated carboxylate residue.
 less than 3 greater than  The sulfur-containing unsaturated carboxylate compound described in  less than 2 greater than  prepared by reacting a sulfur-containing dihydroxy compound with an xcex1,xcex2-unsaturated carboxylic acid derivative represented by general formula (2): 
wherein R11 represents a bivalent organic group; each Xll independently represents oxygen, sulfur, xe2x80x94COOxe2x80x94 or xe2x80x94(CH2)1X12xe2x80x94 (X12 represents oxygen or sulfur and l is an integer of 1 to 3); each R12 independently represents hydrogen or alkyl;,and each R13 independently represents a sulfur-containing substituent.
 less than 4 greater than  The sulfur-containing unsaturated carboxylate compound described in  less than 2 greater than  where the xcex1,xcex2-unsaturated carboxylate residue is selected from the group consisting of (meth)acrylic acid, crotonic acid, tiglic acid, 3,3-dimethylacrylic acid, maleic acid, citraconic acid, 2,3-dimethylmaleic acid, itaconic acid and cinnamic acid residues.
 less than 5 greater than  The sulfur-containing unsaturated carboxylate compound described in  less than 2 greater than  where the bivalent organic group R11 is a moiety represented by a formula selected from the group of formulas (3-a), (4-a), (5-a) and (6-a): 
wherein R31, R32, R33 and R34 independently represent hydrogen, alkyl, alkoxy, nitro or halogen; 
wherein Y41 represents a single bond, xe2x80x94C(R41)2xe2x80x94 (each R41 independently represents hydrogen or methyl), xe2x80x94Oxe2x80x94, xe2x80x94Sxe2x80x94 or xe2x80x94SO2xe2x80x94; R42 and R43 independently represent alkyl, alkenyl, aralkyl, aryl, alkoxy, alkylthio, nitro or halogen; m and n independently represent an integer of 0 to 4; 
wherein each R51 independently represents hydrogen or alkyl; 
wherein R61 and R62 independently represent hydrogen or alkyl.
 less than 6 greater than  The sulfur-containing unsaturated carboxylate compound described in  less than 2 greater than  where the sulfur-containing substituent R13 is a moiety represented by formula (7-a) or (8-a)
R71xe2x80x94Oxe2x80x94xe2x80x83xe2x80x83(7-a)
wherein R71 is a monovalent organic group containing at least one sulfur atom;
R81xe2x80x94Sxe2x80x94xe2x80x83xe2x80x83(8-a)
wherein R81 is a monovalent organic group optionally containing a sulfur atom.
 less than 7 greater than  The sulfur-containing unsaturated carboxylate compound described in  less than 2 greater than  where the sulfur-containing substituent R13 is a moiety represented by formula (9-a): 
wherein R91 and R92 independently represent hydrogen or alkyl or R91 and R92 may be linked together to form a ring; X93 represents oxygen or sulfur; p represents an integer of 0 to 3; and q represents an integer of 1 to 4.
 less than 8 greater than  The sulfur-containing unsaturated carboxylate compound described in  less than 2 greater than  where the bivalent organic group R11 is represented by formula (3-a-i); X11 is oxygen, xe2x80x94COOxe2x80x94 or xe2x80x94(CH2)lX12xe2x80x94 (X12 represents oxygen or sulfur and l is an integer of 1 to 3); R13 is represented by formula (7-a) or (8-a); and R14 is a (meth)acrylic acid residue. 
 less than 9 greater than  The sulfur-containing unsaturated carboxylate compound described in  less than 2 greater than  where the bivalent organic group R11 is represented by formula (4-a-i), (4-a-ii) or (4-a-iii); X11 is oxygen; R13 is represented by formula (7-a) or (8-a); and R14 is a (meth)acrylic acid residue; 
wherein R42 and R43 independently represent hydrogen or methyl; 
wherein each R41 independently represents hydrogen or methyl; 
 less than 10 greater than  The sulfur-containing unsaturated carboxylate compound described in  less than 2 greater than  where the bivalent organic group R11 is represented by formula (5-a-i); X11 is oxygen; R13 is represented by formula (7-a) or (8-a); and R14 is a (meth)acrylic acid residue. 
wherein each R51 independently represents hydrogen or alkyl.
 less than 11 greater than  The sulfur-containing unsaturated carboxylate compound described in  less than 2 greater than  where the bivalent organic group R11 is represented by formula (6-a-i); X11 is oxygen or xe2x80x94COOxe2x80x94; R13 is represented by formula (7-a) or (8-a); and R14 is a (meth)acrylic acid residue. 
 less than 12 greater than  A polymerizable composition comprising the sulfur-containing unsaturated carboxylate compound described in any of  less than 1 greater than  to  less than 11 greater than .
 less than 13 greater than  A cured product prepared by polymerizing the polymerizable composition described in  less than 12 greater than .
 less than 14 greater than  An optical component consisting of the cured product described in  less than 13 greater than .
This invention also provides the following intermediates for preparing the sulfur-containing unsaturated carboxylate compound described in any of  less than 1 greater than  to  less than 11 greater than :
 less than 15 greater than  A hydroxy compound represented by general formula (2): 
wherein R11 represents a bivalent organic group; each X11 independently represents oxygen, sulfur, xe2x80x94COOxe2x80x94 or xe2x80x94(CH2)lX12xe2x80x94 (X12 represents oxygen or sulfur and l is an integer of 1 to 3); each R12 independently represents hydrogen or alkyl; each R13 independently represents a sulfur-containing substituent.
 less than 16 greater than  The hydroxy compound described in  less than 16 greater than  where the bivalent organic group R11 is a moiety represented by a formula selected from the group of formulas (3-a), (4-a), (5-a) and (6-a): 
wherein R31, R32, R33 and R34 independently represent hydrogen, alkyl, alkoxy, nitro or halogen; 
wherein Y41 represents a single bond, xe2x80x94C(R41)2xe2x80x94 (each R41 independently represents hydrogen or methyl), xe2x80x94Oxe2x80x94, xe2x80x94Sxe2x80x94 or xe2x80x94SO2xe2x80x94; R42 and R43 independently represent alkyl, alkenyl, aralkyl, aryl, alkoxy, alkylthio, nitro or halogen; m and n independently represent an integer of 0 to 4; 
wherein each R51 independently represents hydrogen or alkyl; 
wherein R61 and R62 independently represent hydrogen or alkyl.
 less than 17 greater than  A sulfur-containing compound represented by formula (9): 
wherein R91 and R92 independently represent hydrogen or alkyl or R91 and R92 may be linked together to form a ring; R93 represents halogen atom, hydroxyl group or thiol group; p represents an integer of 0 to 3; and q represents an integer of 1 to 4.
The sulfur-containing unsaturated carboxylate compound according to this invention is useful as a monomer for a photocurable polymerizable composition in a variety of applications such as optical materials and dental materials. An optical component produced by curing the polymerizable composition has excellent optical, thermal and mechanical properties; can be produced in an improved yield; has a higher refractive index; and is useful in various applications such as a variety of plastic lenses (typically, an orthodontic eyeglass), substrates for optical information recording media, plastic substrates for a liquid crystal cell and coatings for optical-fibers.
Furthermore, this invention can provide a novel sulfur-containing dihydroxy compound represented by general formula (2) and a novel sulfur-containing compound represented by formula (9) which are very useful as a preparation material for a starting monomer for the above optical resin.
This invention will be described in detail.
A sulfur-containing unsaturated carboxylate compound according to this invention is a novel compound having a structural feature that it intramolecularly comprises a sulfur-containing substituent and at least two xcex1,xcex2-unsaturated carboxylic acid residues, which are each attached to a secondary or tertiary carbon atom via an oxygen atom.
The sulfur-containing unsaturated carboxylate compound of this invention is, although described in later, an unsaturated carboxylate compound typically obtained by an esterified reaction of a sulfur-containing hydroxyl compound having two or more hydroxyl groups which are bonded to a secondary or tertiary carbon atom with xcex1,xcex2-unsaturated carboxylic acids.
The term xe2x80x9cxcex1,xcex2-unsaturated carboxylic acid residuexe2x80x9d means a group derived from xcex1,xcex2-unsaturated carboxylic acids which are one of the starting material, i.e., an acyl residue of which a hydroxyl group is eliminated from a carboxyl group in the xcex1,xcex2-unsaturated carboxylic acid. In the case that the xcex1,xcex2-unsaturated carboxylic acid has 2 or more (plurality) of carboxyl groups, the term means an acyl residue of which a hydroxyl group is eliminated from only one carboxyl group among those.
The sulfur-containing unsaturated carboxylate compound of this invention has two or more of the above unsaturated carboxylic acid residues in its molecule.
The number of the unsaturated carboxylic acid residues is preferably two to five, more preferably two to four, further preferably two or three. Particularly, it is the most preferable that the number of the unsaturated carboxylic acid residues is two.
Another structural feature of the present sulfur-containing unsaturated carboxylate compound is to have a substituent containing sulfur atom. The number of the substituents containing sulfur atom is preferably 2 to 10, more preferably 2 to 8, further preferably 2 to 4.
In the light of desired effects of this invention, the sulfur-containing unsaturated carboxylate according to this invention intramolecularly comprises preferably at least 2, more preferably at least 3, further preferably at least 4 sulfur atoms.
When the sulfur-containing unsaturated carboxylate compound according to this invention is used as an optical component such as a lens, it preferably has a property that a cured product prepared by curing a polymerizable composition comprising the compound has a refractive index (nd) of 1.58 or higher. A refractive index for the cured product is more preferably 1.59 or higher, further preferably 1.60 or higher.
When the sulfur-containing unsaturated carboxylate compound according to this invention is used as an optical component such as a lens, it preferably has a property that a cured product prepared by curing a polymerizable composition comprising the compound has an Abbe number (xcexdd) of 28 or higher, more preferably 30 or higher, further preferably 33 or higher.
A typical example of the sulfur-containing unsaturated carboxylate compound is a sulfur-containing unsaturated carboxylate compound represented by general formula (1).
The sulfur-containing unsaturated carboxylate represented by general formula (1) will be described in detail.
In general formula (1), R11 represents a bivalent organic group, particularly a bivalent aliphatic or aromatic group or a combination thereof. The bivalent organic group R11 may have a substituent or substituents comprising, in addition to carbon and hydrogen atoms, hetero atoms such as oxygen, sulfur and nitrogen atoms. Particularly, it is preferable that a sulfur atom is contained, for achieving a higher refractive index and a higher Abbe number which constitute desired effects of this invention.
The organic group is more preferably selected from the group of C2-C30 alkylenes which are straight, circular or a combination thereof; C5-C30 aralkylenes; C4-C30 arylenes; and moieties where at least two arylenes above are linked via at least one bivalent linker.
When the organic group R11 has a substituent, the substituent may be, for example, selected from the group of alkyl, alkoxy, alkylthio, nitro or halogen (e.g., bromine, iodine or chlorine atom); preferably, C1-C4 alkyl, C1-C4 alkoxy, C1-C4 alkylthio, bromine and iodine; more preferably methyl, methoxy, methylthio and bromine.
The organic group R11 may include, but not limited to, methylene, 1,2-ethylene, 1,1-ethylene, 1-methyl-1,2-ethylene, 1,2-dimethyl-1,2-ethylene, 1,3-trimethylene, 
Among these bivalent organic groups, the organic group R11 is more preferably a group represented by formula (3-a), (4-a), (5-a) or (6-a); 
wherein R31, R32, R33 and R34 independently represent hydrogen, alkyl, alkoxy, nitro or halogen; 
wherein Y41 represents a single bond, xe2x80x94C(R41)2xe2x80x94 (each R41 independently represents hydrogen or methyl), xe2x80x94Oxe2x80x94, xe2x80x94Sxe2x80x94 or xe2x80x94SO2xe2x80x94; R42 and R43 independently represent alkyl, alkenyl, aralkyl, aryl, alkoxy, alkylthio, nitro or halogen; m and n independently represent an integer of 0 to 4; 
wherein each R51 independently represents hydrogen or alkyl; 
wherein R61 and R62 independently represent hydrogen or alkyl.
The bivalent organic group represented by one of formulas (3-a) to (6-a).
In formula (3-a), R31, R32, R33 and R34 independently represent hydrogen, alkyl, alkoxy, nitro or halogen; preferably, hydrogen, optionally substituted straight, branched or circular alkyl, optionally substituted straight, branched or circular alkoxy, nitro or halogen; more preferably, optionally substituted straight, branched or circular C1-C20 alkyl, optionally substituted straight, branched or circular C1-C20 alkoxy, nitro or halogen.
Specific examples of R31, R32, R33 and R34 include hydrogen, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, 2-ethylhexyl, n-octyl, n-decyl, n-dodecyl, n-tetradecyl, n-octadecyl, cyclopentyl, cyclohexyl, 4-tert-butylcyclohexyl, cycloheptyl, cyclooctyl, cyclohexylmethyl, cyclohexylethyl, tetrahydrofurfuryl, 2-methoxyethyl, 2-ethoxyethyl, 2-n-butoxyethyl, 3-methoxypropyl, 3-ethoxypropyl, 3-n-propoxypropyl, 3-n-butoxypropyl, 3-n-hexyloxypropyl, 2-methoxyethoxyethyl, 2-ethoxyethoxyethyl, phenoxymethyl, 2-phenoxyethoxyethyl, chlolromethyl, 2-chloroethyl, 3-chloropropyl, 2,2,2-trichloroethyl, methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, sec-butoxy, n-pentyloxy, n-hexyloxy, 2-ethylhexyloxy, n-octyloxy, n-decyloxy, n-dodecyloxy, n-tetradecyloxy, n-octadecyloxy, cyclopentyloxy, cyclohexyloxy, 4-tert-butylcyclohexyloxy, cycloheptyloxy, cyclooctyloxy, cyclohexylmethoxy, cyclohexylethoxy, 2-methoxyethoxy, 2-ethoxyethoxy, 2-n-butoxyethoxy, 3-methoxypropoxy, 3-ethoxypropoxy, 3-n-propoxypropoxy, 3-n-butoxypropoxy, 3-n-hexyloxypropoxy, 2-methoxyethoxyethoxy, phenoxymethoxy, 2-phenoxyethoxyethoxy, chloromethoxy, 2-chloroethoxy, 3-chloropropoxy, 2,2,2-trichloroethoxy, nitro, fluorine, chlorine, bromine and iodine.
R31, R32, R33 and R34 are more preferably selected from hydrogen, C1-C10 unsubstituted straight or branched alkyl, C1-C10 unsubstituted straight or branched alkoxy, nitro, chlorine and bromine; further preferably, hydrogen, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, tert-butoxy, nitro, bromine and iodine.
Particularly, R31, R32, R33 and R34 are hydrogen.
In formula (4-a), Y41 represents a single bond, xe2x80x94C(R41)2xe2x80x94 (each R41 independently represents hydrogen or methyl), xe2x80x94Oxe2x80x94, xe2x80x94Sxe2x80x94 or xe2x80x94SO2xe2x80x94.
Y41 in formula (4-a) preferably represents a single bond, methylene, ethylidene, isopropylidene, xe2x80x94Sxe2x80x94 or xe2x80x94SO2xe2x80x94; more preferably, a single bond, methylene, isopropylidene, xe2x80x94Sxe2x80x94 or xe2x80x94SO2xe2x80x94; further preferably, a single bond, methylene, isopropylidene or xe2x80x94Sxe2x80x94.
In formula (4-a), R42 and R43 independently represent alkyl, alkenyl, aralkyl, aryl, alkoxy, alkylthio, nitro or halogen.
R42 and R43 are preferably C1-C4 straight alkyl, C5-C10 circular alkyl, C2-C6 straight or circular alkenyl, C5-C20 aralkyl, C6-C20 aryl, C1-C4 straight alkoxy, C5-C12 circular alkoxy, C1-C4 alkylthio, nitro, bromine or iodine; more preferably, methyl, allyl, benzyl, phenyl, methoxy, methylthio or bromine.
In formula (4-a), m and n independently represent an integer of 0 to 4; preferably 0 to 3; more preferably 0 to 2.
A preferable group represented by formula (4-a) is one represented by formula (4-a-i), (4-a-ii) or (4-a-iii); 
wherein R42 and R43 independently represent hydrogen or methyl; 
wherein each R41 represents hydrogen or methyl; 
In formula (5-a), each R51 independently represents hydrogen or alkyl; preferably, hydrogen or C1-C4 straight alkyl; more preferably, hydrogen or methyl.
In formula (6-a), R61 and R62 independently represent hydrogen or alkyl; preferably, hydrogen or C1-C4 straight alkyl; more preferably, hydrogen or methyl.
In general formula (1), each substituent R12 independently represents hydrogen or alkyl; more preferably, hydrogen or methyl; further preferably, hydrogen.
In general formula (1), each R13 independently represents a sulfur-containing substituent comprising at least one sulfur atom.
The substituent R13 is preferably a group represented by formula (7-a):
R71xe2x80x94Oxe2x80x94xe2x80x83xe2x80x83(7-a)
wherein R71 is a monovalent organic group containing at least one sulfur atom; or (8-a):
R81xe2x80x94Sxe2x80x94xe2x80x83xe2x80x83(8-a)
wherein R81 is a monovalent organic group optionally containing a sulfur atom.
In the above formula, the substituent R71 is a monovalent organic group containing at least one sulfur atom. The substituent R71 is preferably alkyl, aralkyl, aryl or acyl containing at least one sulfur atom; more preferably, straight, branched or circular C1-C20 alkyl, C5-C20 aralkyl, C4-C20 aryl or C2-C20 acyl containing at least one sulfur atom. These monovalent organic groups may have a substituent and a hetero atom other than sulfur; e.g., a substituent comprising a heterocycle.
In the above formula, the substituent R81 is a monovalent organic group optionally containing a sulfur atom. The substituent R81 is preferably alkyl, aralkyl, aryl or acyl optionally containing a sulfur atom; more preferably, straight, branched or circular C1-C20 alkyl, C5-C20 aralkyl, C4-C20 aryl or C2-C20 acyl optionally containing a sulfur atom. These monovalent organic groups may have a substituent and a hetero atom other than sulfur; e.g., a substituent comprising a heterocycle. More preferably, the substituent R81 contains a sulfur atom, for achieving desired effects of this invention such as a higher refractive index and a higher Abbe number.
The substituent R13 is more preferably straight, branched or circular alkoxy containing at least one sulfur atom; aralkyloxy containing at least one sulfur atom; aryloxy containing at least one sulfur atom; acyloxy containing at least one sulfur atom; straight, branched or circular alkylthio optionally containing a sulfur atom; aralkylthio optionally containing a sulfur atom; arylthio optionally containing a sulfur atom; or acylthio optionally containing a sulfur atom.
Specific examples of the substituent R13 include, but not limited to, methylthioethoxy, ethylthioethoxy, propylthioethoxy, butylthioethoxy, methylthioethylthioethoxy, methylthioethylthioethylthioethoxy, 2,2-di(methylthio)ethoxy, 2,2-di(ethylthio)ethoxy, 2,2-di(propylthio)ethoxy, 2,2-di(butylthio)-ethoxy, 3,3-di(methylthio)propoxy, 3,3-di(ethylthio)propoxy, 3,3-di(propylthio)ethoxy, 3,3-di(butylthio)ethoxy, (1,3-dithiolan-2-yl)methoxy, 2-(1,3-dithiolan-2-yl)ethoxy, 3-(1,3-dithiolan-2-yl)propoxy, (1,3-dithiolan-4-yl)methoxy, 2-(1,3-dithiolan-4-yl)ethoxy, 3-(1,3-dithiolan-4-yl)propoxy, (1,4-dithian-2-yl)methoxy, 2-(1,4-dithian-2-yl)ethoxy, 3-(1,4-dithian-2-yl)propoxy, (1,3,5-trithian-2-yl)methoxy, 2-(1,3,5-trithian-2-yl)ethoxy, 3-(1,3,5-trithian-2-yl)propoxy, 4-methylthiobenzyloxy, 3-methylthiobenzyloxy, 2-methylthiobenzyloxy, 2,4-di(methylthio)benzyloxy, 3,4-di(methylthio)benzyloxy, 2,4,6-tri(methylthio)benzyloxy, (4-methylthiophenyl)ethoxy, (3-methylthiophenyl)ethoxy, (2-methylthiophenyl)ethoxy, [2,4-di(methylthio)phenyl]ethoxy, [3,4-di(methylthio)phenyl]ethoxy, [2,4,6-tri(methylthio)phenyl]ethoxy, 4-methylthiophenyloxy, 3-methylthiophenyloxy, 2-methylthiophenyloxy, 2,4-di(methylthio)phenyloxy, 2,5-di(methylthio)phenyloxy, 2,6-di(methylthio)phenyloxy, 3,4-di(methylthio)phenyloxy, 3,5-di(methylthio)phenyloxy, 2,4,6-tri(methylthio)phenyloxy, 2,3,4,5,6-penta(methylthio)phenyloxy, methylthio, ethylthio, propylthio, butylthio, methoxyethylthio, butoxyethylthio, methoxypropylthio, cyclohexylthio, 2-methylthioethylthio, 2-ethylthioethylthio, 2-propylthioethylthio, 2-butylthioethylthio, methylthioethylthioethylthio, methylthioethylthioethylthioethylthio, 2,2-di(methylthio)ethylthio, 2,2-di(ethylthio)ethylthio, 2,2-di(propylthio)ethylthio, 2,2-di(butylthio)ethylthio, 3,3-di(methylthio)propylthio, 3,3-di(ethylthio)propylthio, 3,3-di(propylthio)propylthio, 3,3-di(butylthio)propylthio, (1,3-dithiolan-2-yl)methythio, 2-(1,3-dithiolan-2-yl)ethylthio, 3-(1,3-dithiolan-2-yl)propylthio, (1,3-dithiolan-4-yl)methylthio, 2-(1,3-dithiolan-4-yl)ethylthio, 3-(1,3-dithiolan-4-yl)propylthio, (1,3-dithian-2-yl)methylthio, 2-(1,3-dithian-2-yl)ethylthio, 3-(1,3-dithian-2-yl)propylthio, (1,4-dithian-2-yl)methylthio, 2-(1,4-dithian-2-yl)ethylthio, 3-(1,4-dithian-2-yl)propylthio, (1,3,5-trithian-2-yl)methylthio, 2-(1,3,5-trithian-2-yl)ethylthio, 3-(1,3,5-trithian-2-yl)propylthio, benzylthio, 4-methylbenzylthio, 4-methoxybenzylthio, 4-methylthiobenzylthio, 3-methylthiobenzylthio, 2-methylthiobenzylthio, 2,4-di(methylthio)benzylthio, 3,4-di(methylthio)benzylthio, 2,4,6-tri(methylthio)benzylthio, (4-methylthiophenyl)ethylthio, (3-methylthiophenyl)ethylthio, (2-methylthiophenyl)ethylthio, [2,4-di(methylthio)phenyl]elthylthio, [3,4-di(methylthio)phenyl]ethylthio, [2,4,6-tri(methylthio)phenyl]ethylthio, phenylthio, 4-methylphenylthio, 4-methoxyphenylthio, 4-methylthiophenylthio, 3-methylthiophenylthio, 2-methylthiophenylthio, 2,4-di(methylthio)phenylthio, 2,5-di(methylthio)phenylthio, 2,6-di(methylthio)phenylthio, 3,4-di(methylthio)phenylthio, 3,5-di(methylthio)phenylthio, 2,4,6-tri(methylthio)phenylthio, 2,3,4,5,6-penta(methylthio)phenylthio, thiazolin-2-yl-thio, methylthiomethylcarbonyloxy, methylthioethylcarbonyloxy, (1,3-dithiolan-2-yl)carbonyloxy, (1,3-dithiolan-4-yl)carbonyloxy, (1,3-dithian-2-yl)carbonyloxy, (1,4-dithian-2-yl)carbonyloxy, (1,3,5-trithian-2-yl)carbonyloxy, 4-methylthiobenzoyloxy, thiophene-2-carbonyloxy, thiazole-2-carbonyloxy, methylthiomethylcarbonylthio, methylthioethylcarbonylthio, (1,3-dithiolan-2-yl)carbonylthio, (1,3-dithiolan-4-yl)carbonylthio, (1,3-dithian-2-yl)carbonylthio, (1,4-dithian-2-yl)carbonylthio, (1,3,5-trithian-2-yl)carbonylthio, benzoylthio, 4-methylthiobenzoylthio, thiophene-2-carbonylthio and thiazole-2-carbonylthio.
The substituent R13 is particularly preferably a group represented by formula (9-a): 
wherein R91 and R92 independently represent hydrogen or alkyl or R91 and R92 may be linked together to form a ring; X93 represents oxygen or sulfur; p represents an integer of 0 to 3; and q represents an integer of 1 to 4.
In general formula (1), each substituent R14 independently represents an xcex1,xcex2-unsaturated carboxylate residue. As detailed later, a sulfur-containing unsaturated carboxylate compound represented by general formula (1) can be prepared typically by reacting a hydroxy compound represented by general formula (2) with an xcex1,xcex2-unsaturated carboxylic acid, wherein the substituent R14 is a group derived from the reactant, the xcex1,xcex2-unsaturated carboxylic acid. The substituent R14 is preferably, (meth)acrylic acid, crotonic acid, tiglic acid, 3,3-dimethylacrylic acid, maleic acid, citraconic acid, 2,3-dimethylmaleic acid, itaconic acid or cinnamic acid residue. Among these, the substituent R14 is particularly preferably (meth)acrylic acid residue.
Preferable sulfur-containing unsaturated carboxylate compounds represented by general formula (1) include those represented by formulas (1-a), (1-b), (1-c), (1-d), (1-e), (1-f), (1-g), (1-h), (1-i), (1-j) and (1-k). 
wherein R12, R13 and R14 are as defined above; R42 and R43 are each independently hydrogen or methyl; and R51 is independently hydrogen or methyl.
The compound is more preferably one represented by formula (1-a), (1-c), (1-d), (1-e) (1-f), (1-g), (1-h) or (1-i); further preferably one represented by formula (1-a), (1-d), (1-e), (1-f), (1-g), (1-h) or (1-i); particularly preferably one represented by formula (1-a), (1-d) or (1-f).
Specific examples of a sulfur-containing unsaturated carboxylate compounds represented by general formula (1) according to this invention are listed in Table 1 below, but this invention is not limited to those compounds.
A sulfur-containing unsaturated carboxylate comprising a sulfur-containing substituent and at least two xcex1,xcex2-unsaturated carboxylic acid residues, which are each attached to a secondary or tertiary carbon atom via an oxygen atom, according to this invention is a novel compound, but may be suitably prepared by a well-known preparation process.
A sulfur-containing unsaturated carboxylate represented by general formula (1) as a typical example of the sulfur-containing unsaturated carboxylate according to this invention may be suitably prepared by a representative process, via a synthetic route illustrated in Scheme A. 
wherein R11, R12, R13, R14 and X11 are as defined above.
A sulfur-containing unsaturated carboxylate represented by general formula (1) according to this invention can be prepared by a unsaturated carboxylation process employing a well-known synthetic reaction; typically by reacting a sulfur-containing dihydroxy compound represented by general formula (2) with, for example, (a) an xcex1,xcex2-unsaturated carboxylic acid derivatives such as an xcex1,xcex2-unsaturated carboxylic acid and its ester, anhydride and halide, including (meth)acrylic acid, crotonic acid, tiglic acid, 3,3-dimethylacrylic acid, maleic acid, citraconic acid, 2,3-dimethylmaleic acid, itaconic acid and cinnamic acid derivatives; or (b) a halopropionic acid such as 3-chloropropionic acid, 3-bromopropionic acid, 3-chloro-2-methylpropionic acid and 3-bromo-2-methylpropionic acid, or its acid halide to form a halopropionate which is then dehydrohalogenated to provide a (meth)acrylate.
A sulfur-containing dihydroxy compound represented by general formula (2) according to this invention is a novel compound which is useful as a preparation intermediate for a sulfur-containing unsaturated carboxylate represented by general formula (1) according to this invention, in the synthetic route illustrated in Scheme A.
In general formula (2), R11, R12, R13, R14 and X11 are as defined for general formula (1).
Specific examples of a sulfur-containing dihydroxy compound represented by general formula (2) according to this invention are listed in Table 2, but this invention is not limited to those specific compounds.
There will be described a process for preparing a sulfur-containing dihydroxy compound represented by general formula (2) in Scheme (A).
A sulfur-containing dihydroxy compound represented by general formula (2) of this invention may be suitably prepared by reacting a diepoxy compound represented by general formula (10) with a sulfur-containing compound R13xe2x80x94H (specifically a sulfur-containing compound represented by formula (7) or (8), etc.) which is added to the epoxy group via ring opening. The reaction process itself is well known and conducted under conventional reaction conditions. For example, the reaction is suitably conducted in the presence of an appropriate catalyst such as acid or base catalyst, if necessary; 
wherein R11, R12 and X11 are as defined above;
R71xe2x80x94OHxe2x80x83xe2x80x83(7)
wherein R71 is a monovalent organic group comprising at least one sulfur atom;
R81xe2x80x94SHxe2x80x83xe2x80x83(8)
wherein R81 is a monovalent organic group optionally comprising a sulfur atom.
In this reaction, the amount of the sulfur-containing compound which is to be reacted with the diepoxy compound represented by general formula (10) is, but not limited to, per one mole of the diepoxy compound represented by general formula (10), generally 0.1 to 10 moles (0.05 to 5 epoxy equivalents), preferably 0.5 to 5 moles (0.25 to 2.5 epoxy equivalents), more preferably 0.8 to 3 moles (0.4 to 1.5 epoxy equivalents).
The reaction may be conducted neat or in a solvent inert to the reaction. Solvents which may be used include hydrocarbons such as n-hexane, benzene and toluene; ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone; esters such as ethyl acetate and butyl acetate; ethers such as diethylether, tetrahydrofuran and dioxane; halogenated solvents such as dichloromethane, chloroform, carbon tetrachloride, 1,2-dichloroethane and perchlene; and polar solvents such as acetonitrile, N,N-dimethylformamide, N,N-dimethylacetamide and N,N-dimethylimidazolidinone. These solvents may be used in combination of two or more.
A reaction temperature is generally, but not limited to, 0 to 200xc2x0 C., preferably 0 to 100xc2x0 C.
A reaction time depends on various conditions such as a reaction temperature, but generally several minutes to several ten hours.
A sulfur-containing compound represented by formula (9) of this invention is a novel halogenated, hydroxy or thiol compound characterized in that it has an intramolecular cyclic thioacetal structure: 
wherein R91 and R92 independently represent hydrogen or alkyl or R91 and R92 may be linked together to form a ring; R93 represents halogen, hydroxyl or thiol; p represents an integer of 0 to 3; and q represents an integer of 1 to 4.
In formula (9), R91 and R92 independently represent hydrogen or alkyl or R91 and R92 may be linked together to form a ring.
The substituents R91 and R92 are preferably hydrogen or C1-C4 alkyl; more preferably hydrogen, methyl or ethyl. A ring formed by linking R91 and R92 together is preferably a cycloalkane ring, more preferably C5-C7 cycloalkane ring, more preferably cyclohexane.
In formula (9), p is an integer of 0 to 3, preferably 0 to 2, more preferably 0 or 1.
In formula (9), q is an integer of 1 to 4, preferably 1 to 3, more preferably 1 or 2.
In formula (9), R93 represents halogen, hydroxyl or thiol; preferably, halogen or thiol; more preferably thiol. When R93 represents hydroxyl or thiol, formula (9) is a subgroup of formula (7) or (8).
Specific examples of a sulfur-containing compound represented by formula (9) of this invention are listed in Table 3 below.
A sulfur-containing compound represented by formula (9) of this invention in which R93 is halogen can be suitably prepared typically by reacting an aldehyde represented by formula (11) or its acetal derivative with a dithiol represented by formula (12) in the presence of an acid catalyst. 
wherein R91, R92, p and q are as defined above, and R113 represents halogen.
A sulfur-containing compound represented by formula (9) of this invention in which R93 is hydroxyl or thiol can be suitably prepared typically by converting a circular thioacetal represented by formula (9) in which R93 is halogen using a known synthetic chemistry such as alkaline hydrolysis of halogen into hydroxyl, or by reacting the halogen with a thiourea to form a thiuronium salt, which is then treated with an alkali to be converted into thiol.
There will be described in detail a process for preparing a sulfur-containing compound represented by formula (9) of this invention in which R93 is halogen, by reacting an aldehyde represented by formula (11) or its acetal derivative with a dithiol represented by formula (12) in the presence of an acid catalyst.
Examples of an aldehyde represented by formula (11) or its acetal derivative include haloalkylaldehydes such as chloroacetaldehyde, 3-chloropropionaldehyde and 3-bromopropionaldehyde; and dialkylacetal or circular alkyleneacetal derivatives such as 2-chloroacetaldehyde dimethylacetal, 2-chloroacetaldehyde diethylacetal, 2-chloropropionaldehyde dimethylacetal, 2-chloropropionaldehyde diethylacetal, 2-bromopropionaldehyde dimethylacetal, 2-bromopropionaldehyde diethylacetal, 2-bromopropionaldehyde ethyleneacetal [or 2-(2xe2x80x2-bromoethyl)-1,3-dioxolane] and 2-bromopropionaldehyde trimethyleneacetal [or 2-(2xe2x80x2-bromoethyl)-1,3-dioxane].
Examples of a dithiol derivative represented by formula (12) include straight alkanedithiols such as ethanedithiol, 1,2-propanedithiol, 1,3-propanedithiol, 1,2-butanedithiol, 1,3-butanedithiol, 1,4-butanedithiol, 1,2-pentanedithiol, 1,3-pentanedithiol, 1,4-pentanedithiol, 1,2-hexanedithiol, 1,3-hexanedithiol, 1,4-hexanedithiol, 1,2-heptanedithiol, 1,2-octanedithiol, 1,2-nonanedithiol, 1,2-decanedithiol; and
cycloalkanedithiols such as cyclopentane-1,2-dithiol and cyclohexane-1,2-dithiol.
In preparation of a compound represented by formula (9) of this invention where R93 is halogen by reacting an aldehyde represented by formula (11) or its acetal derivative with a dithiol represented by formula (12), the amount of the dithiol is generally, but not limited to, 0.5 to 5 moles, preferably 0.8 to 2 moles, more preferably 0.9 to 1.2 moles per one mole of the aldehyde represented by formula (11) or its acetal derivative.
The reaction may be conducted in the absence or presence of a catalyst such as a protic acid including mineral acids (e.g., hydrochloric acid and sulfuric acid) and organic acids (e.g., acetic acid and propionic acid), and a Lewis acid. In the light of a reaction temperature and a reaction time, it is preferable to conduct the reaction in the presence of a catalyst for accelerating the reaction.
Examples of a reaction catalyst include protic acids such as sulfuric acid, hydrochloric acid, hydrobromic acid, nitric acid, methanesulfonic acid, trifluoromethanesulfonic In acid and p-toluenesulfonic acid; and Lewis acids such as titanium trichloride, titanium tetrachloride, tin dichloride, tin tetrachloride and boron trifluoride-etherate complex.
The amount of the reaction catalyst is generally, but not limited to, 0.001 to 20 moles, preferably 0.01 to 10 moles, more preferably 0.1 to 5 moles per one mole of the aldehyde represented by formula (11) or its acetal derivative.
These reaction catalysts may be used alone or in combination of two or more.
The reaction may be conducted neat or in the presence of a solvent. Examples of a solvent, if used, include hydrocarbons such as benzene, toluene and xylenes; halogenated solvents such as dichloromethane, chloroform, 1,2-dichloroethane, chlorobenzene and dichlorobenzene; and ethers such as diethylether, tetrahydrofuran, dioxane and diethyleneglycol dimethyl ether. These solvents may be used alone or in combination of two or more.
There are no restrictions for the amount of the solvent, but an extremely excessive amount of solvent is not preferable because of, for example, a manufacturing efficiency. It is generally 300-fold by weight or less, preferably 100-fold by weight or less, per the weight of the aldehyde represented by formula (11) or its acetal derivative.
The reaction may be conducted either under an ambient atmosphere or under an inert gas atmosphere. It is preferably conducted under an inert gas atmosphere such as nitrogen and argon for preventing, for example, coloring of a reaction product.
A reaction temperature is preferably, but not limited to, 0xc2x0 C. to a boiling point of a solvent used.
A reaction time depends on a reaction temperature, but may be generally several minutes to several ten hours. A reaction end-point may be determined by tracing the reaction by a known analytical method such as liquid chromatography, thin layer chromatography and IR.
The substituent R93, i.e., halogen, in the compound represented by formula (9) prepared as described above can be suitably converted into thiol by an appropriate known process such as those described in Journal of Organic Chemistry, Vol. 27, pp. 93-95 (1962); and Organic Synthesis, IV, pp. 401-403 (1963). Specifically, in a typical process, a compound represented by formula (9) in which R93 is halogen is suitably reacted with thiourea, and a product is then hydrolyzed using an alkali such as aqueous ammonia and sodium hydroxide to give a compound represented by formula (9) in which R93 is thiol.
The substituent R93, i.e., halogen, in the compound represented by formula (9) prepared as described above can be suitably converted into hydroxyl by an appropriate known process such as those described in Jikken Kagaku Koza, 4th ed., Vol. 20, pp. 49-51 (edited by Japan Chemistry Association) and Synthesis, p. 763 (1986). Specifically, in a typical process, a compound represented by formula (9) in which R93 is halogen is suitably hydrolyzed using an alkali such as sodium hydroxide to give a compound represented by formula (9) in which R93 is hydroxyl.
A sulfur-containing compound represented by formula (9) of this invention can be isolated, after completion of the above reaction, from a reaction mixture by a usual work-up procedure such as neutralization, filtration, solvent extraction, washing with water, phase separation and evaporation. It can be, as necessary, purified by a known treatment or purification process such as distillation, recrystallization, column chromatography and charcoal treatment.
There will be described a process for preparing a sulfur-containing unsaturated carboxylate, especially a sulfur-containing (meth)acrylate using a sulfur-containing dihydroxy compound represented by general formula (2) as a starting material.
As described above, a sulfur-containing dihydroxy compound represented by general formula (2) can be converted into a sulfur-containing unsaturated carboxylate typically by (a) its reaction with (meth)acrylic acid, its ester or its acid halide and then esterification by dehydration, transesterification or dehydrohalogenation; or (b) its reaction with a chloropropionic acid such as chloropropionic acid, its ester and its acid halide to form a chloropropionate, which is then dehydrohalogenation to give a (meth)acrylate.
There will be further described, as the most typical process of the above processes, reaction of a sulfur-containing dihydroxy compound represented by general formula (2) with (meth)acrylic acid, its ester or its acid halide.
Specifically, the reaction can be conducted by an appropriate known process such as those described in J. Org. Chem., 4, 5364 (1980) and Eur. Polym. J., 19, 399 (1983). For example, (a) to a sulfur-containing dihydroxy compound represented by general formula (2) is reacted with (meth)acrylic acid halide (e.g., by adding dropwise) with stirring in the presence of a base; (b) a sulfur-containing dihydroxy compound represented by general formula (2) and (meth)acrylic acid are condensed with dehydration in the presence of a catalyst; or (c) in the presence of a catalyst such as an acid or base catalyst, a sulfur-containing dihydroxy compound is subject to transesterification with a (meth)acrylate derivative [e.g., an alkyl(meth)acrylate such as methyl(meth)acrylate and ethyl(meth)acrylate].
The amount of a (meth)acrylic compound [e.g., (meth)acrylic acid, its ester or its acid halide] to a sulfur-containing dihydroxy compound represented by general formula (2) is generally, but not limited to, per one mole of the dihydroxy compound, 0.1 to 10 moles (0.05 to 5 equivalents per one hydroxyl group), preferably 0.5 to 5 moles (0.25 to 2.5 equivalents per one hydroxyl group), more preferably 0.8 to 3 moles (0.4 to 1.5 equivalents per one hydroxyl group).
The reaction may be conducted neat or in a solvent inert to the reaction. Solvents which may be used include hydrocarbons such as n-hexane, benzene and toluene; ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone; esters such as ethyl acetate and butyl acetate; ethers such as diethylether, tetrahydrofuran and dioxane; halogenated solvents such as dichloromethane, chloroform, carbon tetrachloride, 1,2-dichloroethane and perchlene; and polar solvents such as acetonitrile, N,N-dimethylformamide, N,N-dimethylacetamide and N,N-dimethylimidazolidinone. These solvents may be used in combination of two or more.
A reaction temperature is, but not limited to, a temperature at which the raw material, the (meth)acrylic compound and a reaction product, a (meth)acrylate are not polymerized; generally xe2x88x9278 to 150xc2x0 C., preferably xe2x88x9220 to 120xc2x0 C., more preferably 0 to 100xc2x0 C.
A reaction time depends on a reaction temperature, but may be generally several minutes to 100 hours, preferably 30 minutes to 50 hours, more preferably 1 to 20 hours. The reaction may be terminated in an appropriate conversion while checking a conversion by a known analytical method such as liquid chromatography, thin layer chromatography and IR.
In the reaction of a sulfur-containing dihydroxy compound represented by general formula (2) with (meth)acrylic acid halide, a hydrogen halide such as hydrogen chloride may be formed as a byproduct. A base can be, therefore, used as a dehydrohalogenation agent, including organic bases such as triethylamine, pyridine, picoline, dimethylaniline, diethylaniline, 1,4-diazabicyclo[2.2.2]octane (DABCO), 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) and inorganic bases such as sodium bicarbonate, sodium carbonate, potassium carbonate, lithium carbonate, sodium hydroxide, potassium hydroxide, calcium hydroxide and magnesium oxide.
The amount of such a dehydrohalogenation agent is generally, but not limited to, 0.1 to 10 moles, preferably 0.5 to 5 moles, more preferably 0.8 to 3 moles per one mole of the sulfur-containing dihydroxy compound represented by general formula (2).
In preparation of a sulfur-containing (meth) acrylate represented by general formula (1) of this invention by condensation with dehydration of a sulfur-containing dihydroxy compound represented by general formula (2) and (meth)acrylic acid, it is preferable to use a known esterification catalyst. Examples of such a catalyst include mineral acids such as hydrochloric acid, sulfuric acid, nitric acid, boric acid and phosphoric acid; organic acids such as methanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid and trifluoromethanesulfonic acid; and Lewis acids such as boron trifluoride, aluminum trichloride, titanium tetrachloride, titanium dichloride, tin dichloride and tin tetrachloride.
The amount of the reaction catalyst is preferably, but not limited to, 0.001 to 50 wt %, preferably 0.01 to 30 wt % to the amount of reactants.
It is preferable to remove byproduced water outside the system for accelerating the reaction. It can be accomplished by azeotropic dehydration using a solvent among the above solvents which can be co-evaporated with water; using a dehydrating agent such as molecular sieves; or a combination thereof.
In the above process, an appropriate procedure, for example, as described in JP-A 10-67736 can be employed for reacting a sulfur-containing dihydroxy compound represented by general formula (2) with a halopropionic acid or its acid halide to form a halopropionate, which is then dehydrohalogenated to give a sulfur-containing (meth)acrylate represented by general formula (1).
An unsaturated carboxylate (e.g., crotonate, tiglate, 3,3-dimethylacrylate, maleate, citraconate, 2,3-dimethylmaleate, itaconate or cinnamate) represented by general formula (1) of this invention other than a sulfur-containing (meth)acrylate may be suitably prepared as described in the above process for a (meth)acrylate compound, except using, as a reactant, another unsaturated carboxylic acid such as a crotonic acid compound such as crotonic acid, its ester and its anhydride; a tiglic acid compound such as tiglic acid, its ester and its anhydride; a 3,3-dimethylacrylic acid compound such as 3,3-dimethylacrylic acid, its ester and its anhydride; a maleic acid compound such as maleic acid, its ester and its anhydride; a citraconic acid compound such as citraconic acid, its ester and its anhydride; a 2,3-dimethylmaleic acid compound such as 2,3-dimethylmaleic acid, its ester and its anhydride; an itaconic acid compound such as itaconic acid, its ester and its anhydride; and a cinnamic acid compound such as itaconic acid, its ester, its anhydride and its acid halide, instead of a (meth)acrylic acid compound.
In preparation of a sulfur-containing unsaturated carboxylate compound represented by general formula (1), it is preferable to use a polymerization inhibitor for preventing a product from being polymerized during or after the reaction. Examples of such an inhibitor include various known compounds such as 4-methoxyphenol, hydroquinone and phenothiazine.
The amount of the polymerization inhibitor is generally, but not limited to, 0.01 to 5 wt %, preferably 0.05 to 3 wt % to the amount of a reaction mixture or product in a reaction system.
A sulfur-containing unsaturated carboxylate compound represented by general formula (1) of this invention as a product can be isolated, after completion of the reaction, by a usual treatment or work-up procedure such as neutralization, solvent extraction, washing with water, phase separation and evaporation. The sulfur-containing unsaturated carboxylate compound represented by general formula (1) thus obtained can be also, as necessary, separated and purified by a known process such as distillation, recrystallization and chromatography, to be isolated as a highly pure compound.
When preparing a polymerizable composition, a cured product formed by polymerization of the polymerizable composition or an optical component of this invention, using a sulfur-containing unsaturated carboxylate compound represented by general formula (1) of this invention, the mixture as such may be used without separation or purification.
There will be detailed a polymerizable composition comprising a sulfur-containing unsaturated carboxylate compound represented by general formula (1) of this invention.
A polymerizable composition of this invention comprises a sulfur-containing unsaturated carboxylate compound represented by general formula (1) of this invention and photo- and/or thermal-polymerization initiators, as essential components. The sulfur-containing unsaturated carboxylate compound can be used alone or a plurality of different sulfur-containing unsaturated carboxylates compound can be combined.
A polymerizable composition of this invention may, as necessary, comprise a known polymerizable compound such as a photo- or thermal polymerizable monomer or oligomer, in addition to a sulfur-containing unsaturated carboxylate compound represented by general formula (1), as long as it does not affect desired effects of this invention.
The amount of a sulfur-containing unsaturated carboxylate compound represented by general formula (1) in the above polymerizable composition is generally, but not limited to, at least 10 wt %, preferably at least 20 wt %, more preferably at least 30 wt %, more preferably at least 50 wt % to the overall weight of the polymerizable composition.
There are no restrictions for a polymerization initiator used in a polymerizable composition of this invention, and a variety of known thermal- or photo-initiators may be used.
Photoinitiators includes benzoin, benzil, benzoin methyl ether, benzoin isopropyl ether, acetophenone, 1,1-dimethoxy-1-phenylaceto-phenone, 1,1-dichloroacetophenone, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 2-methyl-1-(4-methylthiophenyl)-2-morpholinolpropan-1-one, N,N-dimethylaminoacetophenone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 1-chloroanthraquinone, 2-amylanthraquinone, 2-isopropylthioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2,4-diisopropylthioxanthone, acetophenone dimethyl ketal, benzophenone, 4-methylbenzophenone, 4,4xe2x80x2-dichlorobenzophenone, 4,4xe2x80x2-bisdiethylaminobenzophenone and Mihira""s ketone. These may be used alone or in combination of two or more.
The amount of a photoinitiator is 0.001 to 50 parts by weight, preferably 0.01 to 30 parts by weight, more preferably 0.1 to 10 parts by weight, more preferably 0.2 to 5 parts by weight, to 100 parts by weight of a sulfur-containing unsaturated carboxylate compound represented by general formula (1).
Thermal initiators include peroxides such as benzoyl peroxide, p-chlorobenzoyl peroxide, diisopropyl peroxycarbonate, di-2-ethylhexyl peroxycarbonate and tert-butyl peroxypivalate; and azo compounds such as azobisisobutyronitrile.
The amount of a thermal initiator is generally 0.001 to 50 parts by weight, preferably 0.01 to 30 parts by weight, more preferably 0.1 to 10 parts by weight, more preferably 0.2 to 5 parts by weight, to 100 parts by weight of a sulfur-containing unsaturated carboxylate compound represented by general formula (1).
Known polymerizable compounds other than a sulfur-containing unsaturated carboxylate compound represented by general formula (1) which may be used as a polymerizable compound in a polymerizable composition of this invention, are, for example, known polymerizable monomers including monofunctional or polyfunctional (meth)acrylates such as methyl(meth)acrylate, butyl(meth)acrylate, 2-ethylhexyl(meth)acrylate, ethylcarbitol(meth)acrylate, lauryl(meth)acrylate, tetracyclododecyl(meth)acrylate, phenoxyethyl(meth)acrylate, nonylphenoxyethyl(meth)acrylate, dicyclopentenyl(meth)acrylate, isobornyl(meth)acrylate, N-n-butyl-O-(meth)acryloyloxyethyl carbamate, acryloylmorpholine, trifluoroethyl(meth)acrylate, tribromobenzyl(meth)acrylate and perfluorooctylethyl(meth)acrylate, ethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, triethylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, 2,2-bis(4-acryloyloxyphenyl)propane, 2,2-bis(4-methacryloyloxyphenyl)propane, bis(4-acryloyloxyphenyl)methane, bis(4-methacryloyloxyphenyl)methane, 4,4xe2x80x2-bis(acryloyloxy)diphenyl sulfide, 4,4xe2x80x2-bis(methacryloyloxy)diphenyl sulfide, 2,2-bis[4-(acryloyloxyethoxy)phenyl]propane, 2,2-bis[4-(methacryloyloxyethoxy)phenyl]propane, 2,2-bis[4-(2-acryloyloxypropoxy)phenyl]propane, 2,2-bis[4-(2-methacryloyloxypropoxy)phenyl]propane, bis[4-(acryloyloxyethoxy)phenyl]methane, bis[4-(methacryloylethoxy)phenyl]methane, bis[4-(2-acryloyloxypropoxy)phenyl]methane, bis[4-(2-methacryloylpropoxy)phenyl]methane, 4,4xe2x80x2-bis(2-acryloyloxyethoxy)diphenyl sulfide, 4,4xe2x80x2-bis(2-methacryloyloxyethoxy)diphenyl sulfide, 4,4xe2x80x2-bis(2-acryloyloxypropoxy)diphenyl sulfide, 4,4xe2x80x2-bis(2-methacryloyloxypropoxy)diphenyl sulfide, 4,4xe2x80x2-bis(2-acryloyloxyethoxy)diphenyl sulfone, 4,4xe2x80x2-bis(2-methacryloyloxyethoxy)diphenyl sulfone, 4,4xe2x80x2-bis(2-acryloyloxypropoxy)diphenyl sulfone, 4,4xe2x80x2-bis(2-methacryloyloxypropoxy)diphenyl sulfone, di(meth)acrylate of ethylene oxide or propylene oxide adducts of 2,2-bis(4-hydroxyphenyl)propane, di(meth)acrylate of ethylene oxide or propylene oxide adducts of bis(4-hydroxyphenyl)methane, trimethylolpropane tri(meth)acrylate, di(pentaerythritol)pentaacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, di(trimethylol)tetraacrylate, di(pentaerythritol)hexaacrylate, 2-(meth)acryloyloxyethyl tris(isocyanulate) and (meth)acryloxypropyl-tris(methoxy)silane; epoxy(meth)acrylates as a reaction product of a (meth)acrylic acid and a various of known monofunctional or 2 or more functional epoxy compound such as phenol glycidyl ether, ethyleneglycol diglycidyl ether, propyleneglycol diglycidyl ether, resorcinol diglycidyl ether, hydroquinone diglycidyl ether, bis(4-hydroxyphenyl)methane (common name: bisphenol-F) diglycidyl ether, 2,2-bis(4-hydroxyphenyl)propane (common name: bisphenol-A) diglycidyl ether, 4,4xe2x80x2-bis(hydroxyphenyl)sulfide diglycidyl ether, 4,4xe2x80x2-bis(hydroxyphenyl)sulfone (common name: bisphenol-S) diglycidyl ether, 4,4xe2x80x2-biphenol diglycidyl ether, 3,3xe2x80x2,5,5xe2x80x2-tetramethyl-4,4xe2x80x2-biphenol diglycidyl ether and tris(2,3-epoxypropyl)isocyanulate; epoxy(meth)acrylates as a reaction product of an epoxy compound such as phenol novolac epoxy resin, cresol novolac epoxy resin, phenol-aralkyl-resin-type epoxy resin, bisphenol epoxy resin with acrylic or methacrylic acid; vinyl compounds such as vinylbenzene, divinylbenzene, trivinylbenzene, isopropenylbenzene, diisopropenylbenzene, triisopropenylbenzene, N-vinylpyrrolidone and N-vinylcaprolactam; allyl-containing compounds such as ethyleneglycol diallyl carbonate, triallyl trimellite and triallyl isocyanurate; and various known polymerizable oligomers such as polyurethane(meth)acrylate, epoxy(meth)acrylate, polyester(meth)acrylate and polyether(meth)acrylate.
The amount of the compound is generally 300 parts by weight or less, preferably 200 parts by weight or less, more preferably 100 parts by weight or less, to 100 parts by weight of a sulfur-containing unsaturated carboxylate compound represented by general formula (1) for more effectively achieving the effects of this invention.
A polymerizable composition of this invention may be prepared specifically by using a sulfur-containing unsaturated carboxylate compound represented by formula (1) of this invention, as necessary, in combination with one or more of the various known polymerizable compounds described above, and after adding any of the above polymerization initiator, blending and/or dissolving them. After, if necessary, removing insolubles and/or foreign matters and fully defoaming at a reduced pressure before polymerization, the polymerizable composition can be used for polymerization and curing. For preparing the polymerizable composition, a variety of known additives can be, as necessary, added, including internal mold release agents, photostabilizers, ultraviolet absorbers, antioxidants, color pigments such as Cyanine Green and Cyanine Blue, dyes, fluidity-regulating agents, and inorganic fillers such as talc, silica, alumina, barium sulfate and magnesium oxide.
A cured product and an optical component comprising the product according to this invention can be prepared by polymerizing and curing the above polymerizable composition. They can be suitably prepared by a variety of known processes; typically by injecting a polymerizable composition obtained as described above into a mold and then polymerizing it by radical polymerization initiated by heat or light, i.e., cast molding.
The mold consists of two mirror-finished templates combined via a gasket made of a soft thermoplastic resin such as polyethylene, ethylene-vinyl acetate copolymer and polyvinyl chloride. The templates may be, for example, a combination of glass-glass, glass-plastic plate, or glass-metal plate. Instead of using the above gasket made of a soft thermoplastic resin, two templates may be combined and fixed with an appropriate fixing means such as a polyester sticky tape.
The templates may be treated by a known procedure such as application of a mold releasing agent.
Radical polymerization may be conducted by heating (thermal polymerization), irradiating light such as UV (photo polymerization) and irradiating xcex3-rays as well as a combination thereof, as described above.
For these processes, thermal polymerization takes several to several ten hours while photo polymerization with, e.g., UV allows curing to be completed several seconds to several minutes. The latter is preferable in the light of improvement in a yield for preparing an optical component of this invention.
For thermal polymerization, a polymerization temperature cannot be specifically defined because it varies depending on various polymerization conditions such as a type of an initiator, but generally 25 to 200xc2x0 C., preferably 50 to 170xc2x0 C.
An optical lens can be formed by, for example, cast molding using light and/or heating as described above (See, e.g., JP-A 60-135901, JP-A 10-67736 and JP-A 10-130250).
It is suitably conducted by, as necessary, defoaming a polymerizable composition comprising a sulfur-containing unsaturated carboxylate compound represented by general formula (1) of this invention prepared as described above by an appropriate procedure; injecting it in a mold and generally polymerizing it by irradiation. Thermal polymerization may be suitably conducted by gradually heating the composition from a lower temperature to a higher temperature.
Furthermore, an optical lens thus obtained may be, if necessary, subject to a variety of physical or chemical treatments such as surface abrasion, antistatic treatment, hard coat treatment, non-reflection coating, dyeing and light-modulating treatment (e.g., photochromic-lens treatment), for improvements such as prevention of reflection; improvement in hardness, abrasion resistance or chemical resistance; and impartation of antifogy or cosmetic property.
A substrate for an optical disk or magnetro-optical disk may be prepared by any of appropriate known processes such as injecting a polymerizable composition comprising a sulfur-containing unsaturated carboxylate compound represented by general formula (1) of this invention prepared as described above into the cavity of a mold for a disk substrate, polymerizing it by, e.g., radical polymerization and, as necessary, post-heating it (See, e.g., JP-As 58-130450, 58-137150 and 62-280008); photopolymerizing it in a mold whose both sides are made of glass (See JP-A 60-2025557); or injecting it optionally in vacuo and then compressing the liquid resin for thermal polymerization (See JP-A 60-203414).
The polymerizable composition of this invention may be photopolymerized to give a cured product or an optical component consisting of the cured product in as short as period of several minutes to several hours. That is, it has a feature that it may be polymerized and molded in a shorter time than an existing thermosetting optical resin such as poly(diethyleneglycoldiallyl carbonate) and polythiourethane.
Furthermore, a cured product and an optical component of this invention are characterized in that they exhibit excellent optical, mechanical and thermal properties as well as a higher refractive index. Examples of the optical component include a variety of plastic lenses (typically, an orthodontic eyeglass), substrates for optical information recording media, plastic substrates for a liquid crystal cell and coatings for optical fibers.